A retrospective study was undertaken on 6 piggeries in north Australia and South Vietnam to define the reproductive performance of sows in the tropics. Reproductive performance was analysed in respect to age of first mating, time of the year, breed and management practices. There was a significant effect of the time of the year at mating on farrowing rate. Highest farrowing rates were achieved when sows were mated during the cool time of the year in the Australian piggeries and during the dry-hot period as opposed to the wet-hot period in Vietnamese piggeries. The number of matings per oestrus and interval between matings influenced both farrowing rate and number of piglets born although an increased litter size at birth was accompanied by an increase in stillbirths and mummified foetuses.